Question: For the past few years, I have dealt with fatigue, heart palpitations, and dizziness. Lately, the dizziness and palpitations have gotten worse, and my left eye jerks. My doctor ordered a CAT scan of the brain which was normal, and she next plans a heart monitor. Will a CAT scan show any neurological problems? And, if it is a heart problem, will a heart monitor detect it?
Dr. Hibberd's Answer:
The evaluation for nystagmus (involuntary eye movements) involves searching for causes of involuntary eye movements in conjunction with a complete history and physical examination along with appropriate lab and nutritional studies. Imaging studies such as a CAT (Computerized Axial Tomography) scan involve radiation exposure, and should be performed to support a suspected cause, and not done just to look at the brain. Also, the CAT is not a functional study, and it's best used for trauma evaluation when hemorrhage is suspected and time is of the essence.
The choice of imaging often depends upon the judgment and needs of your medical consultant(s), and may be modified by the availability of MRI (Magnetic Resonance Imaging) in your area. Suffice to say that CAT scanning involves radiation exposure and is rapidly performed usually within several minutes.
An MRI involves no radiation, is more expensive, and will often reveal more detail. An MRI is usually preferred when time is not of the essence and there are no metallic implants or retained metallic objects that may dislodge and superheat during MRI study. An MRI takes much longer, at least 20-30 minutes, and is not usually regarded as an emergency procedure because of the extensive time it takes to perform. Beware though that an MRI does not always reveal all details of brain vessels. Occasionally, contrast and/or an MRA (magnetic resonance angiography) may be needed when vascular or blood vessel causes are suspected.
Heart problems are evaluated by various studies. Rate and rhythm disturbances will normally be seen on a 24 hour Holter monitor. Conduction issues are often affected by blood chemistry, thyroid and deficiency states that are easily detected by simple blood testing. Ischemic coronary artery disease is investigated by cardiac catheterization or screened for with one of several noninvasive stress testing studies. Even though some centers are advocating coronary CAT scanning to screen for coronary artery disease risk, I believe there are better ways to screen non-emergency patients until we find ways to scan without significant radiation exposure. Structural problems are best initially screened for with ultrasound by a 2D echocardiogram occasionally supplemented with a Doppler study done at the same time as the echo. In addition, be sure your carotid arteries have been screened by ultrasound for evidence of disease. I wish you well.
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